Build a Java application

Client driver: Yugabyte JDBC

The following tutorial shows a small Java application that connects to a YugabyteDB cluster using the topology-aware Yugabyte JDBC driver and performs basic SQL operations. Use the application as a template to get started with YugabyteDB Managed in Java.

Prerequisites

Clone the application from GitHub

Clone the sample application to your computer:

git clone https://github.com/YugabyteDB-Samples/yugabyte-simple-java-app.git && cd yugabyte-simple-java-app

Provide connection parameters

If your cluster is running on YugabyteDB Managed, you need to modify the connection parameters so that the application can establish a connection to the YugabyteDB cluster. (You can skip this step if your cluster is running locally and listening on 127.0.0.1:5433.)

To do this:

  1. Open the app.properties file located in the application src/main/resources/ folder.

  2. Set the following configuration parameters:

    • host - the host name of your YugabyteDB cluster. To obtain a YugabyteDB Managed cluster host name, sign in to YugabyteDB Managed, select your cluster on the Clusters page, and click Settings. The host is displayed under Connection Parameters.
    • port - the port number that will be used by the JDBC driver (the default YugabyteDB YSQL port is 5433).
    • dbUser and dbPassword - the username and password for the YugabyteDB database. If you are using the credentials you created when deploying a cluster in YugabyteDB Managed, these can be found in the credentials file you downloaded.
    • sslMode - the SSL mode to use. YugabyteDB Managed requires SSL connections; use verify-full.
    • sslRootCert - the full path to the YugabyteDB Managed cluster CA certificate.
  3. Save the file.

Build and run the application

First build the application.

$ mvn clean package

Start the application.

$ java -cp target/yugabyte-simple-java-app-1.0-SNAPSHOT.jar SampleApp

If you are running the application on a Sandbox or single node cluster, the driver displays a warning that the load balance failed and will fall back to a regular connection.

You should see output similar to the following:

>>>> Successfully connected to YugabyteDB!
>>>> Successfully created DemoAccount table.
>>>> Selecting accounts:
name = Jessica, age = 28, country = USA, balance = 10000
name = John, age = 28, country = Canada, balance = 9000

>>>> Transferred 800 between accounts.
>>>> Selecting accounts:
name = Jessica, age = 28, country = USA, balance = 9200
name = John, age = 28, country = Canada, balance = 9800

You have successfully executed a basic Java application that works with YugabyteDB Managed.

Explore the application logic

Open the SampleApp.java file in the application /src/main/java/ folder to review the methods.

main

The main method establishes a connection with your cluster via the topology-aware Yugabyte JDBC driver.

YBClusterAwareDataSource ds = new YBClusterAwareDataSource();

ds.setUrl("jdbc:yugabytedb://" + settings.getProperty("host") + ":"
    + settings.getProperty("port") + "/yugabyte");
ds.setUser(settings.getProperty("dbUser"));
ds.setPassword(settings.getProperty("dbPassword"));

// Additional SSL-specific settings. See the source code for details.

Connection conn = ds.getConnection();

createDatabase

The createDatabase method uses PostgreSQL-compliant DDL commands to create a sample database.

Statement stmt = conn.createStatement();

stmt.execute("CREATE TABLE IF NOT EXISTS " + TABLE_NAME +
    "(" +
    "id int PRIMARY KEY," +
    "name varchar," +
    "age int," +
    "country varchar," +
    "balance int" +
    ")");

stmt.execute("INSERT INTO " + TABLE_NAME + " VALUES" +
    "(1, 'Jessica', 28, 'USA', 10000)," +
    "(2, 'John', 28, 'Canada', 9000)");

selectAccounts

The selectAccounts method queries your distributed data using the SQL SELECT statement.

Statement stmt = conn.createStatement();

ResultSet rs = stmt.executeQuery("SELECT * FROM " + TABLE_NAME);

while (rs.next()) {
    System.out.println(String.format("name = %s, age = %s, country = %s, balance = %s",
        rs.getString(2), rs.getString(3),
        rs.getString(4), rs.getString(5)));
}

transferMoneyBetweenAccounts

The transferMoneyBetweenAccounts method updates your data consistently with distributed transactions.

Statement stmt = conn.createStatement();

try {
    stmt.execute(
        "BEGIN TRANSACTION;" +
            "UPDATE " + TABLE_NAME + " SET balance = balance - " + amount + "" + " WHERE name = 'Jessica';" +
            "UPDATE " + TABLE_NAME + " SET balance = balance + " + amount + "" + " WHERE name = 'John';" +
            "COMMIT;"
    );
} catch (SQLException e) {
    if (e.getSQLState().equals("40001")) {
        System.err.println("The operation is aborted due to a concurrent transaction that is" +
            " modifying the same set of rows. Consider adding retry logic for production-grade applications.");
        e.printStackTrace();
    } else {
        throw e;
    }
}

Learn more

Yugabyte JDBC driver